


Something Unexpected

by StargazingAtWords (TheLonelyJournalKeeper)



Series: Fairy Tail Gem Au [3]
Category: Fairy Tail
Genre: Complicated Relationships, Cross-Posted on Tumblr, Fairy Tail Gem Au, Fist Fights, Friendship, Fusion, Gem Fusion, Gen, M/M, Play Fighting, Prompt Fill, gem au
Language: English
Status: Completed
Published: 2016-05-18
Updated: 2016-05-18
Packaged: 2018-06-09 06:44:18
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,832
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6894289
Author URL: https://archiveofourown.org/users/TheLonelyJournalKeeper/pseuds/StargazingAtWords
Summary: <blockquote class="userstuff">
              <p>Natsu picks a fight.</p>
            </blockquote>





	Something Unexpected

**Author's Note:**

  * For [Luna_Myth](https://archiveofourown.org/users/Luna_Myth/gifts).



> Luna Myth prompted: FT Gem AU: Natsu accidentally fuses with Gray while fighting.

Lisanna was away for the day on a mission. Natsu tried not to begrudge her this as she was accompanied by Mirajane and Elfman and they clearly deserved to spend some time together. It made Lisanna so happy to see them again. He really couldn’t be upset by this. 

But still, he was bored without her. She had a way of making every time fun.

And when Natsu was bored he had a way of picking fights. He thought it was a left over trait from when he was a Ruby back on Homeworld. Picking fights with the other Rubies was one of the few acceptable forms of entertainment as it honed their battle skills. 

He thought the practice could apply quite nicely here. After all, it couldn’t hurt to brush up on his solo combat skills in case he needed to tackle some Homeworld gems alone. It would be nice to have the option of keeping Lisanna out of the fighting though he knew she wouldn’t like that. It would keep him occupied until she returned (likely with a good story of their adventures) at the very least. 

Unfortunately, the Crystal Gems were a lot more difficult to pick fights with than the other Rubies. Erza was particularly intolerant of his attempts. 

Fortunately, there was someone he could always count on for a good fight.

That someone was a tall gem in varying shades of black from which he had gotten the name Gray. 

The two had a complicated relationship. Quite frankly, he got on Natsu’s nerves about eighty-five percent of the time. Ten percent of the time the two were actively engaged in a fight and the remaining five percent was spent in a state of mutual disregard for each other. 

At any rate, he made the perfect candidate for a good fight. As much as Natsu hated to admit it, Gray was very skilled in a fight.

Natsu found the Onyx on look out duty, making sure no gems from Homeworld had stumbled upon their base. 

“Hey Gray, you up for a fight?” 

“Can’t you tell I’m busy?” He rolled his eyes. “I can’t afford to get distracted. Do you want Homeworld to sneak up on us?”

“Aw come on!” Natsu complained. “This planet is huge. There’s no way they’ll find us and I’m bored.”

“Tell that to Erza,” the Onyx said irritably. “Go bother someone else. Like Lisanna. Where is she anyway? It’s weird seeing you on your own.” 

“She’s on a mission with Mirajane and Elfman.” 

“Right.” He returned to gazing out over the horizon. 

“Come on, Gray,” Natsu needled. “It’s not like you to back out of a fight. Are you chicken?” 

He rolled his eyes again. “Not in the slightest, flamebrain.” 

“Then fight me! No one’s coming and this is really boring.”

Gray looked between the Ruby and the horizon. “I guess I could afford to kick your ass if it’ll make you go away. It shouldn’t take longer than a few minutes.” He smirked. 

Natsu ignored that last remark, determined to prove him wrong. “Alright!” He grinned, cracking his knuckles. 

Natsu clenched his fist and summoned his gauntlet. 

Gray pressed his fist into his other hand, coming away with a long, jagged shard protruding from the back of his fist, like a piece of sharp, black ice. 

“Ready?” 

“You better believe it.” 

Excitement coursed through Natsu. There was nothing like some friendly sparring to make you feel alive. For him, it wasn’t so much about the act as it was about the feelings. The strain, the exertion, the satisfying contact, the quick dodges. It was about the consequences, every punch or movement had an effect, and the strange sort of connection formed between those engaged in combat. 

Sometimes Natsu thought you got a better understanding of someone based on how they fought than how they spoke. 

He definitely thought that was the case for Gray. On the outside, he was cold and calculating, but he positively came alive during a fight and that was when Natsu liked him best. 

Such was the case now. Gray blocked Natsu’s first punch with the flat of his blade and moved in for a strike of his own. Natsu countered it easily and the two quickly fell into a natural rhythm. 

There was silence but for the occasional sharp cry or grunt of exertion. Seconds stretched into minutes and it turned out Gray was wrong. He did not seem to be winning, but neither did Natsu. 

Each matched the other blow for blow, dodge for dodge, strike for strike. Neither could gain the upper hand and at some point, it no longer became about winning. It became about the rhythm. 

Natsu ducked to avoid getting decapitated, but slipped. Gray instinctively grabbed his wrist and Natsu grabbed his in return. 

Their gems glowed brightly. It was with great surprise that Natsu felt the very familiar sensation of fading away, but before he could decide what to do about it, he was already gone.

* * *

 

“What the hell is this?!” The fusion quickly answered his own question. “Fusion. This is fusion. I-you-Natsu and Gray…fused? What the hell?! I didn’t even know you could fuse by fighting! It was accident! Well of course it was an accident. Like I’d-you’d-we’d ever fuse on purpose.” 

He looked down at himself. He was taller than Natsanna though not by much and he was mottled hues of red and black. “Four arms,” he murmured, clenching four fists. “Two eyes. I wonder-“ 

He made a fist and Natsu’s gauntlet appeared. He slammed that fist against his other palm and it metamorphosed. Now both of his fists were encased in spiked gauntlets, red with black stakes protruding from each of the knuckles. 

“Alright,” he smirked. “I could get used to this. Let’s test ‘em out. I feel pretty powerful.” He jumped down from the look-out point and surveyed the area for a target. He found one in the form of a large tree which he obliterated in two swift punches. 

His smirk widened. “Fusions are pretty strong. I bet I could even take down Erza! No, that sounds like a terrible idea. Or does it?” 

Conflicting opinions warred in his head and for a moment, his form shimmered, he thought he might split apart before he solidified. 

“It doesn’t.” He decided. “Just this once. After all, she’d want to be told about any new fusions.” He smirked again. “After I win the fight, of course.” 

The fusion set off in search of the red Quartz, a fight humming in his hard light blood. 

It didn’t take long to find her and with the components set on a solitary task, the fusion was quite stable. He didn’t harbor any delusions however. Once he was done having his fun, Natsu and Gray would part ways immediately. 

In the meantime, Erza was long over due to be defeated. 

Her eyes widened when she saw him, but the fusion didn’t know whether she recognized him or not. It didn’t matter anyways. 

“Erza!” He called with a confident grin. 

“Who are-you’re not Homeworld. You know my name,” she frowned, eyes searching him for clues. 

“Doesn’t matter,” said the fusion. “I wanna fight. I’m strong enough to beat you now.” 

She laughed softly, momentarily stopping her search for his gems to look him in the eye. “You think so?” 

“I know so,” the fusion said confidently. He readied his weapons. 

“I’d love to see whether that’s true or not,” she said calmly. “But I’d rather know why Gray isn’t on look out duty and how Natsu managed to fuse with him. Better yet,” she continued, her voice turning icy. “Tell me why you decided to leave the camp unguarded to assuage your wounded ego.” 

Oh _damn_. They’d been caught. Conflicting answers swirled in his brain and his physical form flickered and dissolved, spitting out two separate gems, both of whom were yelling. 

“It’s his fault! I didn’t mean to fuse with him! I was on guard duty like you asked when he showed up and demanded a fight!” 

“It’s not _my_ fault! I didn’t mean to fuse with you either, idiot! And you’re the one who agreed to fight!” 

“It was _your_ dumb idea to fight Erza!” 

“You can’t say that! We were fused! Maybe it was _your_ idea!” 

“Idiot! I would never suggest something as stupid as that!” 

“Silence!” Erza admonished, prying the two apart as they looked ready to start another fight. “Gray! Return to your post! Natsu, tell me what happened!” Her voice was stern and left no room for argument. 

The pair jumped and Gray walked off to the look-out point, muttering darkly about how this was all Natsu’s fault. 

Natsu held his tongue and refrained from pointing out that Gray had been just in charge of the fusion as he had been which is to say…not very. 

Erza was silent for a moment, but Natsu didn’t dare leave. She would speak when she was good and ready. He wished she would hurry up. The silence made him uncomfortable. 

“You said it was an accident,” she said. Her voice was no longer quite as angry, taking on a more intrigued tone. “Explain.” 

“Well uh, it was an accident! We weren’t even dancing. Like I would _try_ to fuse with Gray.” 

“So what were you doing? Gray mentioned a fight.” 

“Right! We were fighting! And then we were fused.” 

“You mean to tell me you were distracting Gray from guard duty with a fight?” 

“Oh,” Natsu said. What was the right answer here? He didn’t think there was one. “….yes?” 

She sighed wearily. “Judging from the fact that Gray hasn’t sounded the alarm, we seem to be okay, but don’t do that again.” 

“Well no one else wanted to fight!” 

“ _Don’t_ do that again,” she repeated with a more threatening edge to her voice. 

Natsu remembered she was annoyed enough as is. “Yes, ma’am.” 

“You say the two of you were fighting as usual? And then you fused?” 

Natsu nodded. 

“This is unexpected,” she said mildly. “It’s a shame the two of you unfused so quickly. I would’ve liked to have tested out your capabilities.” 

Natsu made a face. “We didn’t mean to unfuse. We just kind of fell apart. It was weird. It was like when…like when Natsanna saw Mirajane and Elfman. I didn’t know who they were, but Lisanna did and the conflicting emotions broke our fusion.” 

“Interesting. It seems your and Gray’s fusion is less stable than Natsanna.” 

“Definitely,” Natsu agreed. “A lot less fun too.” 

Erza smiled. “I suppose that would make sense. Very well. You may go.” 

Relieved, he turned to go. Maybe Lisanna would be back by now. 

“Oh but Natsu?” Erza added. 

“Yes?” 

“I still would’ve won.” 

Natsu had already made up his mind not to fuse with Gray again, but he couldn’t help but see that as a challenge. Maybe….maybe he would have to talk to Gray about this. 


End file.
